Evidence for Late-stage Eruptive Mass Loss in the Progenitor to SN2018gep, a Broad-lined Ic Supernova: Pre-explosion Emission and a Rapidly Rising Luminous Transient

Anna Y.Q. Ho, Daniel A. Goldstein, Steve Schulze, David K. Khatami, Daniel A. Perley, Mattias Ergon, Avishay Gal-Yam, Alessandra Corsi, Igor Andreoni, Cristina Barbarino, Eric C. Bellm, Nadia Blagorodnova, Joe S. Bright, E. Burns, S. Bradley Cenko, Virginia Cunningham, Kishalay De, Richard Dekany, Alison Dugas, Rob P. FenderClaes Fransson, Christoffer Fremling, Adam Goldstein, Matthew J. Graham, David Hale, Assaf Horesh, Tiara Hung, Mansi M. Kasliwal, N. Paul M. Kuin, S. R. Kulkarni, Thomas Kupfer, Ragnhild Lunnan, Frank J. Masci, Chow Choong Ngeow, Peter E. Nugent, Eran O. Ofek, Maria T. Patterson, Glen Petitpas, Ben Rusholme, Hanna Sai, Itai Sfaradi, David L. Shupe, Jesper Sollerman, Maayane T. Soumagnac, Yutaro Tachibana, Francesco Taddia, Richard Walters, Xiaofeng Wang, Yuhan Yao, Xinhan Zhang

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

We present detailed observations of ZTF18abukavn (SN2018gep), discovered in high-cadence data from the Zwicky Transient Facility as a rapidly rising (1.4 ± 0.1 mag hr-1) and luminous (Mg,peak = -20 mag) transient. It is spectroscopically classified as a broad-lined stripped-envelope supernova (Ic-BL SN). The high peak luminosity (Lbol ≳ 3 × 1044 erg s-1), the short rise time (trise = 3 days in g band), and the blue colors at peak (g-r ∼ -0.4) all resemble the high-redshift Ic-BL iPTF16asu, as well as several other unclassified fast transients. The early discovery of SN2018gep (within an hour of shock breakout) enabled an intensive spectroscopic campaign, including the highest-temperature (Teff ≳ 40,000 K) spectra of a stripped-envelope SN. A retrospective search revealed luminous (Mg ∼ Mr ≈ mag) emission in the days to weeks before explosion, the first definitive detection of precursor emission for a Ic-BL. We find a limit on the isotropic gamma-ray energy release E γ,iso < 4.9 × 10 48 erg, a limit on X-ray emission LX < 1040 erg s-1, and a limit on radio emission ν Lν ≲ 1037 erg s-1. Taken together, we find that the early (< 10 days) data are best explained by shock breakout in a massive shell of dense circumstellar material (0.02 M) at large radii (3 × 1014 cm) that was ejected in eruptive pre-explosion mass-loss episodes. The late-time (> 10 days) light curve requires an additional energy source, which could be the radioactive decay of Ni-56.

Original languageEnglish
Article number169
JournalAstrophysical Journal
Volume887
Issue number2
DOIs
StatePublished - Dec 20 2019

Fingerprint

Dive into the research topics of 'Evidence for Late-stage Eruptive Mass Loss in the Progenitor to SN2018gep, a Broad-lined Ic Supernova: Pre-explosion Emission and a Rapidly Rising Luminous Transient'. Together they form a unique fingerprint.

Cite this